\(\dfrac{17}{103}< \dfrac{19}{113}\)

\(3+3^2+3^3+3^4\)

\(=3\left(1+3+3^2+3^3\right)\)

\(=3\cdot40\)

\(=3\cdot10\cdot4⋮4\left(dpcm\right)\)

\(2+2^2+2^3+....+2^{2022}\)

\(=\left(2+2^2\right)+\left(2^3+2^4\right)+...+\left(2^{2021}+2^{2022}\right)\)

\(=2\left(1+2\right)+2^3\left(1+2\right)+...+2^{2021}\left(1+2\right)\)

\(=2\cdot3+2^3\cdot3+...+2^{2021}\cdot3\)

\(=3\left(2+2^3+...+2^{2011}\right)⋮3\left(dpcm\right)\)

\(S=2+2^2+2^3+...+2^{10}\) 

\(S=\left(2+2^2\right)+\left(2^3+2^4\right)+...+\left(2^9+2^{10}\right)\) (5 cặp )

\(S=2\left(1+2\right)+2^3\left(1+2\right)+..+2^9\left(1+2\right)\)

\(S=2\cdot3+2^3\cdot3+...+2^9\cdot3\)

\(=3\left(2+2^3+..+2^9\right)⋮3\left(dpcm\right)\)

chỉ tôi ae=)))))

`5^3 - 5.(4+x)=15`

`5.(4+x)=5^3-15`

`5.(4+x)=125-15`

`5.(4+x)=110`

`4+x=110:5`

`4+x=22`

`x=22-4`

`x=18`

Vậy `x=18`

53 - 5 ( 4 + x ) = 15 

= 125 - 5 ( 4 + x ) = 15

= 5 ( 4 + x )  = 125 - 15

= 5 ( 4 + x ) = 110

= 4+x = 110:5

= 4 + x = 22

= x = 22 - 4

= x = 18

a, 6.3.9.2.18 = (6.3).(9.2).18 =  18.18.18 = 18³ 

2.4.8.16.4  = (8.2).(4.4).16 = 16.16.16 = 16³ 

c, 7.7.7.7.7 = 7⁵ 

d, 103. 102 . 10 = 10^{3 + 2 + 1} = 10⁶

a, 6.3.9.2.18 = (6.3).(9.2).18 =  18.18.18 = 183 

2.4.8.16.4  = (8.2).(4.4).16 = 16.16.16 = 163 

c, 7.7.7.7.7 = 75 

d, 103. 102 . 10 = 103 + 2 + 1 = 106

1515/2424 = 1515: 303/ 2424: 303 = 5/8

1515/2424 = 1515: 303/ 2424: 303 = 5/8